Wine industry sources do not agree on the level of taint. Cork manufacturers admit to about one percent and folks who want to sell screw caps or artificial corks claim up to one in three has a degree of taint that can be detected by professional tasters. The guys over at winspectator.com say that fifteen percent of the bottles that they open for their tastings are rejected as tainted by corks.

That ties in with my own experience. As a family, we get through around 200 bottles a year. For many years, we lived in Germany. Almost all wine sold there is sold in traditional glass bottles with cork seals. Once or twice a month I would have to pour a bottle away as it was too badly tainted even for cooking. Wine that was slightly tainted but still just drinkable would be a weekly experience. That was with wine from France, Italy, Chile, Australia and South Africa. The only exception was New Zealand and what was different about NZ wine was that it was almost exclusively in screw caps.

We more recently spent a year in Ireland where wine is pretty much universally available in screw top bottles. Two bottles thrown away in the year and one of those was one of the handful that we bought with a cork seal.